I’ve got a mistake, I have a certificate for my domain martin-abadie.fr which works but, for my subdomain cloud.martin-abadie.fr I’ve got the following error in my web-browser Google Chrome :
NET::ERR_CERT_COMMON_NAME_INVALID
Unable to verify that this server is indeed cloud.martin-abadie.fr, because its security certificate is from domain martin-abadie.fr.
I solved my problem by removing all .conf files and .https files and re-config by default 000-default.conf and default-ssl.conf.
Then, I create a site.conf file which contains my domain declaration, then cloud.conf which contains the sub-domain declaration.
Finally I ran Letsencrypt certification, which ends with success.
Thank you for watching my post, and for trying to help me! I hope it will help those who are in my case